Many systems for transferring electrical energy between objects in relative motion are known. Such systems, however, typically use brushes or wiper arms making physical contact on contact rings in rotary devices or on linear contact surfaces in devices in relative translational motion. However, there are some unavoidable problems associated with apparatus employing direct physical contact between elements in relative motion. Systems that involve direct mechanical or physical contact tend to be relatively maintenance-intensive, if only because the contact areas are susceptible to corrosion, which affects both durability and reliability and may result from the action of ambient pollutants, e.g., substances in the surrounding air, or due to intermittent sparking during relative movements during use.
The contact elements are also subject to physical wear due to friction at the relatively moving contact surfaces. Even further, where there is significant vibration between the relatively moving elements, there will be both physical wear and perhaps erosion wear due to intermittent sparking. Sparking can cause a fire hazard where flammable and volatile substances are present, as can often occur in a workshop, mine, or the like. Electrical sparking can also occur to nearby conducting objects. Furthermore, the exposed contact surfaces which are electrically charged relative to ground may create a shock hazard to personnel and electrical fire hazards due to possible shorting to adjacent conductive objects or in the presence of moisture.
There is, therefore, a need for an apparatus and a system for transferring electrical power between two objects in relative motion, without physical contact, across a defined gap between the objects, in an efficient and reliable manner. The system must be equally reliable whether the objects are in rotation or translation relative to one another. The present invention is intended to address these concerns.